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At least 775 records · Page 43Linked to original sources
USGS2025

A 21st Century butterfly net: Using eDNA to detect the imperiled Dakota skipper

The development of environmental DNA (eDNA) methods for terrestrial arthropods could be transformative for the difficult task of assessing the status of species of conservation concern. The primary goal of this study was to investigate the efficacy of detecting the Dakota skipper ( Hesperia dacotae ) from its DNA left behind on inflorescences as a means of inferring species presence. We developed and tested a novel qPCR assay and validated the assay in both controlled and field contexts. Using captive animals at the Minnesota Zoo, we found that the number of skippers in an enclosure increased the probability of skipper DNA detection. In the field, Dakota skipper DNA was found on 14% (11 of 81) of inflorescences collected. All detections were from narrowleaf purple coneflower ( Echinacea angustifolia ). Known visitation of an inflorescence by Dakota skipper prior to sample collection was not a strong predictor of either skipper DNA presence or amount of DNA, but skipper eDNA was detected at 60% (3 of 5) of sites where skippers were observed and 33% (1 of 3) of sites where skippers were not observed. These findings demonstrate successful application of a targeted-species approach to eDNA sampling for butterflies in the field. Taken together, our findings indicate that this method could provide a novel and useful source of data for assessing occupancy trends of butterflies without capturing or even observing them in the wild.

Minnesota, North Dakota, South Dakota↗
USGS2021

Acoustic tag retention and tagging mortality of juvenile cisco Coregonus artedi

Release of hatchery-reared juvenile cisco ( Coregonus artedi ) is an important tool for recovering Great Lakes populations, but post-release survival is unknown. Telemetry using small acoustic tags provides opportunities to assess the efficacy of hatchery-reared fish releases. However, better understanding of the tolerance of juvenile cisco to acoustic tags is needed. Juvenile cisco mortality and tag retention as a function of tag size:body size (Relative Tag Weight, RTW) was observed for 30 d post tag implantation in the laboratory. Tag loss and mortality increased with RTW. A single mortality occurred for RTW ≤ 3% and tag retention and survival was <50% for RTW > 7.0%. Logistic regression predicted >95% survival and tag retention to 30 d for RTW < 2.5%, with full survival of study fish for RTW of ≤2%. Sedation and surgery times did not affect survival of tagged fish, but results of anesthesia-only and sham surgeries highlight the need to minimize handling effects for effective acoustic telemetry studies. Our findings clarify thresholds of RTW and indicate that juvenile cisco can receive acoustic tag implants. Observing these limitations can improve the effectiveness of acoustic telemetry to assess success of cultured juvenile fish releases for conservation or restoration of native forage fish populations. Evaluation of the effects of acoustic tags over longer time periods and under environmental conditions, like those at release sites, are needed to further validate this technology.

Journal of Great Lakes Research↗
USGS2014

Controls of vegetation structure and net primary production in restored grasslands

1. Vegetation structure and net primary production (NPP) are fundamental properties of ecosystems. Understanding how restoration practices following disturbance interact with environmental factors to control these properties can provide insight on how ecosystems recover and guide management efforts. 2. We assessed the relative contribution of environmental and restoration factors in controlling vegetation structure, above- and below-ground investment in production across a chronosequence of semiarid Conservation Reserve Program (CRP) fields recovering from dryland wheat cropping relative to undisturbed grassland. Importantly, we determined the role of plant diversity and how seeding either native or introduced perennial grasses influenced the recovery of vegetation properties. 3. Plant basal cover increased with field age and was highest in CRP fields seeded with native perennial grasses. In contrast, fields seeded with introduced perennial grasses had tall-growing plants with relatively low basal cover. These vegetation structural characteristics interacted with precipitation, but not soil characteristics, to influence above-ground NPP (ANPP). Fields enrolled in the CRP program for >7 years supported twice as much ANPP as undisturbed shortgrass steppe in the first wet year of the study, but all CRP fields converged on a common low amount of ANPP in the following dry year and invested less than half as much as the shortgrass steppe in below-ground biomass. 4. ANPP in CRP fields seeded with native perennial grasses for more than 7 years was positively related to species richness, whereas ANPP in CRP fields seeded with introduced perennial grasses were controlled more by dominant species. 5. Synthesis and applications. Seeding with introduced, instead of native, perennial grasses had a strong direct influence on vegetation structure, including species richness, which indirectly affected NPP through time. However, the effects of restoring either native or introduced grasses on NPP were secondary to low water availability. Therefore, restoration strategies that maximize basal cover and below-ground biomass, which promote water acquisition, may lead to high resilience in semiarid and arid regions.

Colorado↗
USGS2017

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors

Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr −1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species ( n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata‐level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species‐specific approaches to examine contributing factors to recent distributional changes and for comprehensive conservation planning for climate change adaptation.

Global Change Biology↗
USGS2012

Forest Succession and Maternity Day roost selection by Myotis septentrionalis in a mesophytic hardwood forest

Conservation of summer maternity roosts is considered critical for bat management in North America, yet many aspects of the physical and environmental factors that drive roost selection are poorly understood. We tracked 58 female northern bats ( Myotis septentrionalis ) to 105 roost trees of 21 species on the Fort Knox military reservation in north-central Kentucky during the summer of 2011. Sassafras ( Sassafras albidum ) was used as a day roost more than expected based on forest stand-level availability and accounted for 48.6% of all observed day roosts. Using logistic regression and an information theoretic approach, we were unable to reliably differentiate between sassafras and other roost species or between day roosts used during different maternity periods using models representative of individual tree metrics, site metrics, topographic location, or combinations of these factors. For northern bats, we suggest that day-roost selection is not a function of differences between individual tree species per se , but rather of forest successional patterns, stand and tree structure. Present successional trajectories may not provide this particular selected structure again without management intervention, thereby suggesting that resource managers take a relatively long retrospective view to manage current and future forest conditions for bats.

Kentucky↗
USGS1999

Demography of the Yellowstone grizzly bears

We undertook a demographic analysis of the Yellowstone grizzly bears ( Ursus arctos ) to identify critical environmental factors controlling grizzly bear vital rates, and thereby to help evaluate the effectiveness of past management and to identify future conservation issues. We concluded that, within the limits of uncertainty implied by the available data and our methods of data analysis, the size of the Yellowstone grizzly bear population changed little from 1975 to 1995. We found that grizzly bear mortality rates are about double in years when the whitebark pine crop fails than in mast years, and that the population probably declines when the crop fails and increases in mast years. Our model suggests that natural variation in whitebark pine crop size over the last two decades explains more of the perceived fluctuations in Yellowstone grizzly population size than do other variables. Our analysis used demographic data from 202 radio-telemetered bears followed between 1975 and 1992 and accounted for whitebark pine ( Pinus albicaulis ) crop failures during 1993–1995. We used a maximum likelihood method to estimate demographic parameters and used the Akaike Information Criteria to judge the significance of various independent variables. We identified no independent variables correlated with grizzly bear fecundity. In order of importance, we found that grizzly bear mortality rates are correlated with season, whitebark pine crop size (mast vs. nonmast year), sex, management-trapping status (never management-trapped vs. mangement-trapped once or more), and age. The mortality rate of bears that were management-trapped at least once was almost double that of bears that were never management-trapped, implying a source/sink (i.e., never management-trapped/management-trapped) structure. The rate at which bears move between the source and sink, estimated as the management-trapping rate ( h ), is critical to estimating the finite rate of increase, λ͞ . We quantified h by estimating the rate at which bears that have never been management-trapped are management-trapped for the first time. It differed across seasons, was higher in nonmast than mast years, and varied with age. We calculate that λ͞ = 1.00 from 1975 to 1983 (four mast and five nonmast years) and 1.02 from 1984 to 1995 (seven mast and five nonmast years). Overall, we find that λ͞ = 1.01 ± 0.04 (mean ± 1 se ) from 1975 to 1995. Our models suggest that future management should concentrate on the threats to whitebark pine, such as those posed by white pine blister rust, global warming, and fire suppression. As is currently widely recognized by Yellowstone land managers, our model also suggests that future management must compensate for the increased grizzly bear mortality that is likely to be caused by an increasing number of humans in Yellowstone.

Idaho, Montana, Wyoming↗
USGS2012

Extreme weather and experience influence reproduction in an endangered bird

Extreme weather events, such as droughts and heat waves, are expected to become more severe and more frequent in the coming years, and understanding their impacts on demographic rates is of increasing interest to both evolutionary ecologists and conservation practitioners. An individual's breeding probability can be a sensitive indicator of the decision to initiate reproductive behavior under varying environmental conditions, has strong fitness consequences, and can be considered the first step in a life history trade-off between allocating resources for breeding activities or self-survival. Using a 14-year time series spanning large variation in climatic conditions and the entirety of a population's breeding range, we estimated the effects of extreme weather conditions (drought) on the state-specific probabilities of breeding and survival of an endangered bird, the Florida Snail Kite ( Rostrhamus sociabilis plumbeus ). Our analysis accounted for uncertainty in breeding status assignment, a common source of uncertainty that is often ignored when states are based on field observations. Breeding probabilities in adult kites (>1 year of age) decreased during droughts, whereas the probability of breeding in young kites (1 year of age) tended to increase. Individuals attempting to breed showed no evidence of reduced future survival. Although population viability analyses of this species and other species often implicitly assume that all adults will attempt to breed, we find that breeding probabilities were significantly <1 for all 13 estimable years considered. Our results suggest that experience is an important factor determining whether or not individuals attempt to breed during harsh environmental conditions and that reproductive effort may be constrained by an individual's quality and/or despotic behavior among individuals attempting to breed.

Florida↗
USGS2003

Lake belt study area: High-resolution seismic-reflection survey, Miami-Dade County Florida

Executive Summary The Northwest Dade County Freshwater Lake Plan Area (commonly referred to as the Lake Belt Area) is vital to the future planning and development of southeastern Florida. This area is located within one of the most environmentally sensitive parts of the state – the eastern borders of the Everglades National Park (ENP). The Lake Belt Area and Water Conservation Area BB (WCA BB) provide half of the limestone mining resources used in the state every year. Starting in the mid-1800s canals and levees were built in the area to drain and help develop economic and water resources including protection from floods and droughts. These construction projects have changed the natural water flow (hydropattern and hydroperiod) through the hydrologic system. Changes to the hydropattern and hydroperiod of the area have also had an adverse impact by disrupting the normal breeding patterns of species within the Everglades ecosystem

Florida↗
USGS2020

Altitude of the potentiometric surface in the Mississippi River Valley alluvial aquifer, spring 2018

A potentiometric-surface map for spring 2018 was created for the Mississippi River Valley alluvial (MRVA) aquifer using available groundwater-altitude data from 1,126 wells completed in the MRVA aquifer and from the altitude of the top of the water surface in area rivers from 66 streamgages. Personnel from Arkansas Natural Resources Commission, Arkansas Department of Health, Arkansas Geological Survey, Illinois Department of Agriculture, Illinois State Water Survey, Louisiana Department of Natural Resources, Louisiana Department of Transportation and Development, Mississippi Department of Environmental Quality, Missouri Department of Natural Resources, Yazoo Mississippi Delta Joint Water Management District, U.S. Department of Agriculture-Natural Resources Conservation Service, and U.S. Geological Survey (USGS) routinely collect groundwater-level data from wells screened in the MRVA aquifer. The USGS and the U.S. Army Corps of Engineers routinely collect data on river stage and streamflow for the rivers overlying the MRVA aquifer area. The potentiometric-surface map for 2018 was created utilizing existing groundwater and surface-water altitudes to support investigations to characterize the MRVA aquifer as part of the USGS Water Availability and Use Science Program. Sufficient data were available to map the potentiometric surface of the MRVA aquifer for spring 2018 for about 87 percent of the aquifer area. The potentiometric contours ranged from 10 to 340 feet above North American Vertical Datum of 1988. The regional direction of groundwater flow was generally to the south-southwest, except in areas of groundwater-altitude depressions, where groundwater flowed into the depression, and near rivers, where flow can be from aquifer to the river or from the river into the aquifer. There are large depressions in the potentiometric-surface map in the lower one-half of the Cache region and in most of the Grand Prairie and Delta regions.

Mississippi River Valley alluvial aquifer↗
USGS2022

Balancing model generality and specificity in management-focused habitat selection models for Gunnison sage-grouse

Identifying, protecting, and restoring habitats for declining wildlife populations is foundational to conservation and recovery planning for any species at risk of decline. Resource selection analysis is a key tool to assess habitat and prescribe management actions. Yet, it can be challenging to map suitable resource conditions across a wide range of ecological contexts and use the resulting models to identify effective and universal habitat improvement actions. We developed a management-centric modeling approach that sought to balance the need to evaluate the consistency of key habitat conditions and improvement actions across multiple, distinct populations, while allowing context-specific environmental variables and spatial scales to nuance selection responses that form the basis of location-specific management prescriptions. To demonstrate this approach, we developed a set of habitat selection models for Gunnison sage-grouse ( Centrocercus minimus ), a threatened species under the U.S. Endangered Species Act. Conservation, species recovery, and habitat management efforts are needed in six isolated satellite populations (San Miguel, Crawford, Piñon Mesa, Dove Creek, Cerro Summit-Cimarron-Sims, and Poncha Pass) where environmental conditions differ, and the already small number of birds are declining. We used multi-scale and seasonal resource selection analyses to quantify relationships between environmental conditions and sites used by animals. All models included key habitat variables often altered through management actions to assess their differential influences across models. We found important similarities and differences among satellites, indicating that, although some rules of thumb are generally well-grounded, the consideration of population-specific environmental differences could increase the efficiency of local habitat improvement actions. Sage-grouse also had diverse responses to resource conditions at different scales, indicating that regional spatial (e.g., landscape) and local patch scale can differentially influence expected habitat improvements associated with where such management actions are implemented. Although context variables such as topography cannot be manipulated, sage-grouse associations revealed information that could guide the siting of improvement actions. This approach to balancing management objectives associated with habitat assessment may benefit spatially-structured populations with different environmental contexts and species with complex habitat needs and associations.

Colorado↗
USGS2006

Shorebird roost-site selection at two temporal scales: Is human disturbance a factor?

1. Roost-site selection in shorebirds is governed by ambient factors, including environmental conditions and human disturbance. Determination of the extent to which these factors affect roost use and the associated implications for shorebird habitat protection is important for conservation strategies and informed management of human recreational use of these habitats. Shorebird conservation as a whole is a high priority world-wide because a large proportion of shorebird species is in decline. However, little is understood about the consistency of roost use by different species, what conditions affect species-specific roost-site selection, and at what spatial and temporal scales conditions influence selection. 2. We studied high-tide roost-site selection by eight species of non-breeding shorebirds on a critically important stopover and wintering refuge. We calculated spatial and temporal variability in roost use for each species based on counts and consistency of incidence. We then examined roost-site selection in relation to structural, environmental and human disturbance factors, and how this varied across spatial and temporal scales. 3. Most roosts were used less than 50% of the time, although larger roosts were used more consistently. This varied among species, with red knot Calidris canutus tending to concentrate at a few roosts and American oystercatcher Haematopus palliatus, dowitcher Limnodromus griseus and Limnodromus scolopaceus and ruddy turnstone Arenaria interpres more diffusely distributed among roosts. 4. At an annual scale, the principal factors affecting shorebird presence at roosts were roost length (size), local region, substrate and aspect. The extent and direction of these effects varied among species. Among years, red knots avoided roosts that had high average boat activity within 1000 m, but disturbance did not appear to be a factor for other species. 5. Daily roost use was influenced primarily by wind speed and the ability of roosts to provide shelter from the wind. Only dowitchers appeared to track daily disturbance, avoiding prospective roosts when boat activity within 100 m was high. 6. Synthesis and applications. Our findings emphasize the need to consider species-specific differences in temporal- and spatial-scale effects of roost-site selection factors, including human disturbance, when employing conservation measures for shorebirds. We suggest that conservation management should aim to provide a wide range of potential roosts (both natural and artificial) that could be used under different wind conditions and that are within reasonable travelling distance of preferred feeding areas. Roost use is often highly variable, and monitoring efforts must take this into account before making inferences about changes in use or selection of roost sites. ?? 2006 The Authors.

Journal of Applied Ecology↗
USGS2020

Metabarcoding assays for the detection of freshwater mussels (Unionida) with environmental DNA

Freshwater mussels of the order Unionida are a widely distributed taxon that are important in maintaining freshwater ecosystems and are also highly imperiled throughout the world. Monitoring of mussel populations with environmental DNA (eDNA) is an attractive alternative to traditional methods because it is noninvasive and requires less labor and taxonomic knowledge from field personnel. We developed eDNA metabarcoding assays specific to freshwater mussels and tested them at six sites in the Clinch River, located in the southeastern United States. Our objective was to determine the utility of eDNA metabarcoding for future monitoring of mussel populations and restoration efforts in this watershed. Two metabarcoding assays that target the mitochondrial DNA regions of the cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit (ND1) genes were developed and tested. Our assays appear to be order specific, amplifying members from the two families found in North America, Unionidae and Margaritiferidae, while not amplifying nontarget fish or other bivalve species. From the field collected samples, our assays together detected 19 species, eight of which are listed as federally endangered. The assays also detected 42%, 58%, and 54% of the species identified by recent quantitative visual mussel surveys at three sampling sites. Increased sampling effort by processing a greater water volume or number of samples will likely increase species detections. These eDNA metabarcoding assays may enable enhanced monitoring of freshwater mussel assemblages and subsequently inform conservation efforts.

Virginia↗
USGS2023

Data integration reveals dynamic and systematic patterns of breeding habitat use by a threatened shorebird

Incorporating species distributions into conservation planning has traditionally involved long-term representations of habitat use where temporal variation is averaged to reveal habitats that are most suitable across time. Advances in remote sensing and analytical tools have allowed for the integration of dynamic processes into species distribution modeling. Our objective was to develop a spatiotemporal model of breeding habitat use for a federally threatened shorebird (piping plover, Charadrius melodus ). Piping plovers are an ideal candidate species for dynamic habitat models because they depend on habitat created and maintained by variable hydrological processes and disturbance. We integrated a 20-year (2000–2019) nesting dataset with volunteer-collected sightings (eBird) using point process modeling. Our analysis incorporated spatiotemporal autocorrelation, differential observation processes within data streams, and dynamic environmental covariates. We evaluated the transferability of this model in space and time and the contribution of the eBird dataset. eBird data provided more complete spatial coverage in our study system than nest monitoring data. Patterns of observed breeding density depended on both dynamic (e.g., surface water levels) and long-term (e.g., proximity to permanent wetland basins) environmental processes. Our study provides a framework for quantifying dynamic spatiotemporal patterns of breeding density. This assessment can be iteratively updated with additional data to improve conservation and management efforts, because reducing temporal variability to average patterns of use may cause a loss in precision for such actions.

Montana, North Dakota, South Dakota↗
USGS2020

Ontogenetic shifts in mesohabitat use of young-of-year Rio Grande blue sucker in the Big Bend region of the Rio Grande

Alteration of flow regimes by anthropogenic activities is one of the primary environmental problems in riverine systems. Understanding how hydrologic conditions can affect ontogenetic habitat shifts of imperiled fishes is important in order to develop conservation and management strategies for each life-history stage. We examined relationships between the abundance of young-of-the-year (YOY) Rio Grande Blue Sucker and various abiotic variables in the Trans-Pecos region of the Rio Grande in Texas, USA. We used open N -mixture modeling to better understand the factors affecting ontogenetic habitat shifts of the imperiled aridland river fish. In addition, we examined differences in Rio Grande Blue Sucker total length among three mesohabitat types (pool, riffle, and run). The results of open N -mixture modeling suggested that as pool area increased, the abundance of YOY Rio Grande Blue Sucker increased. Total length of YOY Rio Grande Blue Sucker also significantly differed among the three mesohabitat types. The total lengths of YOY Rio Grande Blue Sucker in pool habitats were lower than in other mesohabitats, suggesting that YOY Rio Grande Blue Sucker undergo ontogenetic habitat shifts into greater current velocity habitats as they grow. The habitat associations we documented support the growing body of research emphasizing the importance of maintaining sufficient and appropriately timed flows to avoid prolonged low flows that limit habitat availability for native fish species during sensitive life stages in the Rio Grande and other aridland rivers.

Texas↗
USGS2018

A social–ecological perspective for riverscape management in the Columbia River Basin

Riverscapes are complex, landscape-scale mosaics of connected river and stream habitats embedded in diverse ecological and socioeconomic settings. Social–ecological interactions among stakeholders often complicate natural-resource conservation and management of riverscapes. The management challenges posed by the conservation and restoration of wild salmonid populations in the Columbia River Basin (CRB) of western North America are one such example. Because of their ecological, cultural, and socioeconomic importance, salmonids present a complex management landscape due to interacting environmental factors (eg climate change, invasive species) as well as socioeconomic and political factors (eg dams, hatcheries, land-use change, transboundary agreements). Many of the problems in the CRB can be linked to social–ecological interactions occurring within integrated ecological, human–social, and regional–climatic spheres. Future management and conservation of salmonid populations therefore depends on how well the issues are understood and whether they can be resolved through effective communication and collaboration among ecologists, social scientists, stakeholders, and policy makers.

Columbia River Basin↗
USGS2005

Threats, conservation strategies, and prognosis for suckers (Catostomidae) in North America: insights from regional case studies of a diverse family of non-game fishes

Catostomid fishes are a diverse family of 76+ freshwater species that are distributed across North America in many different habitats. This group of fish is facing a variety of impacts and conservation issues that are somewhat unique relative to more economically valuable and heavily managed fish species. Here, we present a brief series of case studies to highlight the threats such as migration barriers, flow regulation, environmental contamination, habitat degradation, exploitation and impacts from introduced (non-native) species that are facing catostomids in different regions. Collectively, the case studies reveal that individual species usually are not threatened by a single, isolated factor. Instead, species in general face numerous stressors that threaten multiple stages of their life history. Several factors have retarded sucker conservation including widespread inabilities of field workers to distinguish some species, lack of basic natural history and ecological knowledge of life history, and the misconception that suckers are tolerant of degraded conditions and are of little social or ecological value. Without a specific constituent group lobbying for conservation of non-game fishes, all such species, including members of the catostomid family, will continue to face serious risks because of neglect, ignorance, and misunderstanding. We suggest that conservation strategies should incorporate research and education/outreach components. Other conservation strategies that would be effective for protecting suckers include freshwater protected areas for critical habitat, restoration of degraded habitat, and design of catostomid-friendly fish bypass facilities. We believe that the plight of the catostomids is representative of the threats facing many other non-game freshwater fishes with diverse life-history strategies globally.

Biological Conservation↗
USGS2006

The role of reproductive behavior in the conservation of fishes: examples from the Great Plains riverine fishes

Recovery efforts for threatened and endangered fish species are hampered by lack of knowledge of their reproductive ecology. Habitat requirements and environmental stimuli necessary for reproduction are often unknown and vary widely among species. For Great Plains riverine fishes, this is often complicated by the high turbidity of the system in which the species occur, which precludes direct visual observation of behavior. Innovative methods for collectng behavioral data are required to better understand the conditions necessary for successful reproduction.

American Currents↗
USGS2026

Potential for bird-based biotic indices in watershed assessments: A review of methods, applications, and suggestions for improvement

Birds are sensitive to changes in environmental conditions, and metrics such as species diversity, abundance, and guild composition that describe community-level responses to anthropogenic disturbance can be useful indicators of ecosystem condition. We reviewed published studies (56) of bird-based biotic indices developed for diverse ecosystems in 14 countries to evaluate their efficacy for bioassessments. The major categories of indices used included the index of biotic integrity (IBI; 18% of studies), the bird community index (BCI; 13%), and the index of ecological condition (IEC; 7%), with numerous specialized variants comprising the remaining 62% of studies, including indices adapted for specific ecosystems such as grasslands, wetlands, and urban areas. Index performance varied geographically, highlighting the importance of localized calibration. While few studies applied bird indices at landscape and regional scales, applications that included guild-based classification and habitat-specific metrics demonstrated potential for bird-based ecosystem monitoring and assessment. Bird communities were reliable ecological indicators at regional scales when indices incorporated locally derived disturbance and habitat gradients. This regional reliability indicates that expanding bird-based indices to watershed extents is feasible, especially given the availability of extensive resources such as citizen science bird data. There is an abundance of citizen science bird monitoring programs that potentially provide data for use in watershed-scale avian IBIs. Avian indices that combine data from multiple taxa, community-based metrics, and variables describing habitat quality can provide rigorous tools for watershed bioassessment and evidence-based conservation policy implementation.

Environmental Reviews↗